Statewide September 2013

Alaska Statewide Climate Summary

September 2013

Temperature

September started off warmer than normal and continued this trend until the 16th, where the first negative deviation was recorded for the month, which lasted for nine more days, with the remainder of the month mixed with positive and negative deviations. The mean temperature for all 20 First Order Stations was 45.7°F, matching the long term mean exactly. Annette reported the highest mean temperature for the month at 56.1°F, which was also 2.3°F over the long-term mean. Yakutat held the highest positive deviation from normal at 2.9°F over its long-term mean of 48.4. Following Yakutat with positive deviations exceeding 2°F were Homer (2.8°F), Annette and Valdez (both 2.3°F).

Altogether, temperatures for the month were mixed with 8 stations reported higher than normal temperatures, while the remaining 12 were colder than normal, with Kotzebue having the highest negative deviation, being 3.0°F colder than the expected temperature of 49.6°F. Other fairly substantial negative deviations exceeding 2°F were found for Nome (2.9°F) and McGrath (-2.5°F).

Station

Temperature

Observed (°F)

Normal (°F)

Delta (°F)

Anchorage

48.0

48.6

-0.6

Annette

56.1

53.8

2.3

Barrow

31.2

32.1

-0.9

Bethel

44.4

45.6

-1.3

Bettles

39.0

40.6

-1.6

Cold Bay

49.5

48.1

1.4

Delta Junction

42.6

43.9

-1.4

Fairbanks

43.8

44.9

-1.1

Gulkana

45.1

43.3

1.8

Homer

50.9

48.1

2.8

Juneau

51.9

50.0

1.9

King Salmon

47.0

47.6

-0.6

Kodiak

50.1

49.4

0.7

Kotzebue

39.4

42.3

-3.0

McGrath

42.2

44.6

-2.5

Nome

39.9

42.8

-2.9

St. Paul Island

45.0

45.3

-0.3

Talkeetna

47.3

47.5

-0.2

Valdez

49.6

47.3

2.3

Yakutat

51.3

48.4

2.9

Daily mean temperature deviation from the normal temperature for the mean of the 20 first order stations for September 2013.

For September five new daily high temperature records were set at Cold Bay, Annette, Homer, Juneau, and King Salmon.

Temperature Records

Date

Station

Element

New Record

Old Record

Year of old Record

09/01/13

King Salmon

High Temperature

70

67

1996

09/11/13

Annette

High Temperature

78

77

1960

09/15/13

Valdez

High Temperature

67

62

1989

09/20/13

Cold Bay

High Temperature

60

56

2005

09/28/13

Valdez

High Temperature

61

60

1920

Precipitation

Precipitation for September was slightly above normal for the State, with 119% of normal. 11 of the 20 stations reported above normal values, while 9 stations reported values below normal, mostly coastal stations. These are in ascending order King Salmon with 65% of the expected value, Homer (72%), Annette (77%), and Nome (81%).

Anchorage had the greatest positive deviation from normal, with 5.85", or 196% of the expected amount of 2.99". Following Anchorage was Barrow (190%), Talkeetna (184%) and McGrath (167%). Further, in September three stations (Bettles, Barrow and Nome) reported snowfall events. The amount of snowfall for this month was especially remarkable for Bettles, as 6.9” of snow were measured.

Station

Precipitation

Observed (in)

Normal (in)

Delta (in)

Delta (%)

(%)

Anchorage

5.85

2.99

2.86

96%

196%

Annette

7.50

9.79

-2.29

-23%

77%

Barrow

1.37

0.72

0.65

90%

190%

Bethel

2.52

2.75

-0.23

-8%

92%

Bettles

1.49

1.91

-0.42

-22%

78%

Cold Bay

4.91

4.73

0.18

4%

104%

Delta Junction

0.85

1.03

-0.18

-17%

83%

Fairbanks

1.74

1.10

0.64

58%

158%

Gulkana

2.58

1.58

1.00

63%

163%

Homer

2.39

3.31

-0.92

-28%

72%

Juneau

7.53

8.64

-1.11

-13%

87%

King Salmon

2.08

3.19

-1.11

-35%

65%

Kodiak

7.54

7.35

0.19

3%

103%

Kotzebue

2.02

1.58

0.44

28%

128%

McGrath

4.15

2.49

1.66

67%

167%

Nome

1.98

2.45

-0.47

-19%

81%

St. Paul Island

3.01

2.99

0.02

1%

101%

Talkeetna

7.94

4.32

3.62

84%

184%

Valdez

15.34

9.61

5.73

60%

160%

Yakutat

18.53

21.11

-2.58

-12%

88%

Daily mean precipitation deviation from the normal for the 20 first order stations for September 2013.

Numerous daily record precipitation events were set for September, occurring throughout the month. Notable records include Bethel on the 1st of the month shattering a record from 1924, and Ketchikan on the 19th September, receiving over 1.6" more than its previous record. Furthermore, Anchorage tied the record of 1919 for the most consecutive rainy days (18).

Precipitation Records

Date

Station

Element

New Record

Old Record

Year of old Record

09/01/13

Bethel

Precipitation

1.47

0.69

1924

09/01/13

McGrath

Precipitation

1.26

0.60

1960

09/02/13

McGrath

Precipitation

0.86

0.67

1962

09/11/13

Fairbanks

Precipitation

0.75

0.68

1991

09/12/13

Nome

Precipitation

0.70

0.65

1985

09/13/13

Kotzebue

Precipitation

0.51

0.40

1974

09/19/13

Ketchikan

Precipitation

5.13

3.52

1950

09/19/13

Petersburg

Precipitation

1.57

1.43

1992

09/20/13

St. Paul

Precipitation

0.61

0.50

1991

09/24/13

St. Paul

Precipitation

0.63

0.62

2012

09/25/13

McGrath

Precipitation

0.72

0.39

1996

09/26/13

Cold Bay

Precipitation

0.94

0.85

1985

This infrared satellite image from the National Weather Service shows storm system affecting the Southcentral and Interior portions of Alaska on September 11th, 2013. A record amount of rain was reported for Fairbanks on this day.

Newsworthy Events

High winds were a constant problem various times during the month for Alaska. On the 3rd strong winds and heavy rain caused an advisory warning for the Elliott and Dalton highways. Then on the 20th storms caused four cruise ships to bypass Ketchikan, causing an estimated economic loss of $1.4 million.Later, on the 25th the last 2 cruise ships scheduled to land in Sitka for the season cancelled their port calls due to poor weather.

Sporadic earthquakes also struck various cities this month. On the 10th a 4.1 magnitude earthquake affected Anchorage, centered 15 miles northeast of the city. On the 15th a 6.0 magnitude earthquake was recorded near the Andreanof Islands, about 383 miles from Dutch Harbor.

This information consists of preliminary climatological data compiled by the Alaska Climate Research Center, Geophysical Institute, University of Alaska Fairbanks. This summary is based on the 20 first order stations in Alaska operated by the National Weather Service. Extreme events of other stations are also mentioned. It should be noted that the new climate normals for the time period of 1981-2010 are applied for the calculations of the deviations, and they can be slightly different from the old normals (1971-2000), which were in use up until end of August 2011.